The Amiga changed the computer industry. It was based on a multitasking operating system, rivaled the graphics power of some workstations and was affordable enough for home users. Unfortunately, Commodore struggled to maintain Amiga's lead, and through a number of bizarre business decisions (refusing to license the Amiga design to Sun), went bankrupt. Read about the history of the Commodore Amiga at Low End Mac.

Actually I always thought Tramiel was the one who made Commodore grow. When he moved (had to move?) to Atari, it was the time of the C64. Amiga was financed by Atari before Commodore managed to sneak in. Then he had his own problems at Atari: the ST was nice but competing with the Amiga was really impossible at that point.

The way I see it, Commodore killed the Amiga by not realising how rapidly IBM compatible systems were evolving. Around 1992/93, when the A1200 was launched, MS-DOS based machines came equipped with Sound Blasters and VGA or SVGA. It was really way too late.